Stability Of State Research Articles

From “Big White” army to White Paper Protests: China’s gendered pandemic war and feminist interventions

ABSTRACT In response to the COVID-19 pandemic, many nation-states adopted militarized measures for rapid containment. China notably implemented extreme and enduring war-like procedures. This study aims to explore the implications of securitizing the pandemic through a feminist lens and suggest ethical and equitable strategies for understanding emergencies and coping with future crises. Employing discourse-based online ethnography, it analyzes social dynamics in China’s “pandemic war,” examining how gender and (in)security are co-constructed and the role of feminist activism within an authoritarian context. This article argues that framing the pandemic as war reinforces a masculinist stance of dominance, prioritizing state stability over human rights and security. State-centric securitization perpetuates state authority, gendered social hierarchies, and structural violence. The exclusionary nature of this approach created new avenues for feminist activism, both online and offline, advocating for marginalized groups, raising social and gender awareness, challenging state narratives, and fostering collective resistance. Drawing lessons from Chinese feminist initiatives during COVID-19, this study calls for alternative crisis responses focused on care, equity, ethics, and collaboration.

Exploring the molecular pathways of the activation process in PPARγ recurrent bladder cancer mutants.

The intricate involvement of Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) in glucose homeostasis and adipogenesis is well-established. However, its role in cancer, particularly luminal bladder cancer, remains debated. The overexpression and activation of PPARγ are implicated in tumorigenesis. Specific gain-of-function mutations (M280I, I290M, and T475M) within the ligand-binding domain of PPARγ are associated with bladder cancer and receptor activation. The underlying molecular pathways prompted by these mutations remain unclear. We employed a dual-basin structure-based model (db-SBM) to explore the conformational dynamics between the inactive and active states of PPARγ and examined the effects of the M280I, I290M, and T475M mutations. Our findings, consistent with the existing literature, reveal heightened ligand-independent transcriptional activity in the I290M and T475M mutants. Both mutants showed enhanced stabilization of the active state compared to the wild-type receptor, with the I290M mutation promoting a specific transition route, making it a prime candidate for further study. Electrostatic analysis identified residues K303 and E488 as pivotal in the I290M activation cascade. Biophysical assays confirmed that disrupting the K303-E488 interaction reduced the thermal stabilization characteristic of the I290M mutation. Our study demonstrates the predictive capabilities of combining simulation and cheminformatics methods, validated by biochemical experiments, to gain insights into molecular activation mechanisms and identify target residues for protein modulation.

Hydrogen-Bond-Assisted Catalysis: Hydroxylation of Paclitaxel by Human CYP2C8.

Paclitaxel (PTX, or Taxol), a chemotherapeutic agent widely employed in the treatment of various cancers, undergoes metabolic transformations through the cytochrome P450 enzymes CYP3A4 and CYP2C8. CYP3A4 catalyzes the aromatic hydroxylation reaction of PTX, whereas CYP2C8 demonstrates a distinct reactivity pattern, producing 6α-hydroxypaclitaxel via alkane hydroxylation. Despite the significant impact of PTX metabolism on its anticancer efficacy, the detailed mechanisms underlying these transformations have remained largely unclear. In this study, we employed hybrid quantum mechanics and molecular mechanics (QM/MM) calculations to elucidate the mechanism of PTX metabolism by human CYP2C8. Our QM/MM results reveal that the hydroxylation of PTX by CYP2C8 follows an atypical rebound mechanism. Either of the two hydrogen atoms at the C6 position of PTX can be abstracted, leading to a common radical intermediate. Although the subsequent rebound barrier is unusually high, stereochemical scrambling is unlikely, as the rebound barrier for the formation of the 6α-hydroxylated PTX─the actual product─is significantly lower than that for the 6β-hydroxylated metabolite. Thus, product selectivity is determined by the non-rate-determining rebound step. Furthermore, the hydroxyl group at the C7 position of PTX plays a catalytic role by facilitating the hydrogen abstraction and rebound steps. Our study also confirms a pronounced stability of the transition state in the high-spin sextet spin state, enabled by the enzyme's specific substrate positioning.

Stereoelectronic Tuning of Bioinspired Nonheme Iron(IV)-Oxo Species by Amide Groups in Primary and Secondary Coordination Spheres for Selective Oxygenation Reactions.

Two mononuclear iron(II) complexes, [(6-amide2-BPMEN)FeII](OTf)2 (1) and [(6-amide-Me-BPMEN)FeII(OTf)](OTf) (2), supported by two BPMEN-derived (BPMEN = N1,N2-dimethyl-N1,N2-bis(pyridine-2-yl-methyl)ethane-1,2-diamine) ligands bearing one or two amide functionalities have been isolated to study their reactivity in the oxygenation of C-H and C═C bonds using isopropyl 2-iodoxybenzoate (iPr-IBX ester) as the oxidant. Both 1 and 2 contain six-coordinate high-spin iron(II) centers in the solid state and in solution. The 6-amide2-BPMEN ligand stabilizes an S = 1 iron(IV)-oxo intermediate, [(6-amide2-BPMEN)FeIV(O)]2+ (1A). The oxidant (1A) oxygenates the C-H and C═C bonds with a high selectivity. Oxidant 1A, upon treatment with 2,6-lutidine, is transformed into another oxidant [{(6-amide2-BPMEN)-(H)}FeIV(O)]+ (1B) through deprotonation of an amide group, resulting in a stronger equatorial ligand field and subsequent stabilization of the triplet ground state. In contrast, no iron-oxo species could be observed from complex 2 and [(6-Me2-BPMEN)FeII(OTf)2] (3) under similar experimental conditions. The iron(IV)-oxo oxidant 1A shows the highest A/K selectivity in cyclohexane oxidation and 3°/2° selectivity in adamantane oxidation reported for any synthetic nonheme iron(IV)-oxo complexes. Theoretical investigation reveals that the hydrogen bonding interaction between the -NH group of the noncoordinating amide group and Fe═O core smears out the equatorial charge density, reducing the triplet-quintet splitting, and thus helping complex 1A to achieve better reactivity.

Mathematical Modeling of Dengue Disease Transmission Dynamics

Objectives: This study developed a compartmental ordinary differential equation model to investigate dengue transmission dynamics within a human population. The model stratified the population into susceptible, exposed, infected, and recovered classes, incorporating key epidemiological factors. Methods: Model equilibrium analysis was conducted to determine the stability of disease-free and endemic states. The basic reproduction number (R₀) was calculated to quantify the potential for disease spread. Additionally, sensitivity analysis was performed to assess the impact of key parameters on model outcomes. Findings: Results indicate that reducing mosquito biting rates and increasing human recovery rates are effective strategies for controlling dengue transmission. The model exhibits backward bifurcation, suggesting that even when R₀ is less than one, the disease can persist in the population under certain conditions. Novelty: This study presents a novel modeling framework that can inform the development of targeted prevention and management strategies for dengue. Keywords: Dengue, Mathematical Model, Ordinary differential equations, Basic reproduction number, Sensitivity analysis

Photo‐Induced Ultrafast Charge Transfer and Air‐Stable Radical Formation in Tetraphenylpyrene Derivatives

AbstractStable organic radicals generated by photo‐excitation hold applications in molecular switching devices and information storage. It remains challenging to develop photo‐generated radical materials with rapid response and air stability in the solid state. Here, we report a structure based on 1,3,6,8‐tetraphenylpyrene derivative (Py‐TTAc) displaying photo‐induced radicals with air stability in the solid state. Photo‐induced electron transfer, exposed to a 365 nm ultraviolet lamp for 1 minute, affords radicals in Py‐TTAc powder as confirmed by electron paramagnetic resonance (EPR) spectroscopy. The maximum radical concentration reaches 2.21 % after continuous irradiation for 1 hour and recurs more than 10 times without any chemical degradation. The mechanistic study according to the femtosecond transient absorption (fsTA) and X‐ray technology suggests that the radicals are derived from photo‐induced symmetry‐breaking charge separation (SB‐CS) and stabilized through non‐covalent interactions. The photo‐generated stable radical system is employed in anti‐counterfeiting paper and optoelectronic device applications. This study will provide insights into the development of photoactive organic radical materials.

Photo-Induced Ultrafast Charge Transfer and Air-Stable Radical Formation in Tetraphenylpyrene Derivatives.

Stable organic radicals generated by photo-excitation hold applications in molecular switching devices and information storage. It remains challenging to develop photo-generated radical materials with rapid response and air stability in the solid state. Here, we report a structure based on 1,3,6,8-tetraphenylpyrene derivative (Py-TTAc) displaying photo-induced radicals with air stability in the solid state. Photo-induced electron transfer, exposed to a 365 nm ultraviolet lamp for 1 minute, affords radicals in Py-TTAc powder as confirmed by electron paramagnetic resonance (EPR) spectroscopy. The maximum radical concentration reaches 2.21 % after continuous irradiation for 1 hour and recurs more than 10 times without any chemical degradation. The mechanistic study according to the femtosecond transient absorption (fsTA) and X-ray technology suggests that the radicals are derived from photo-induced symmetry-breaking charge separation (SB-CS) and stabilized through non-covalent interactions. The photo-generated stable radical system is employed in anti-counterfeiting paper and optoelectronic device applications. This study will provide insights into the development of photoactive organic radical materials.

Uncertain Logistic Population Model with Allee Effect

By considering the influence of various uncertain noises, we established an uncertain Logistic population model with Allee effect, which was characterized by an uncertain differential equation. Firstly, we obtained the solution of the model, and discussed the stability of the equilibrium state. Secondly, the unknown parameters in the model were estimated by using the generalized moment estimation method under the framework of uncertainty theory. Finally, the parameter estimations of the model and the properties of the solution were explained by an example analysis.

The Influence of Strategic Media on Nation Building: The Case of Sudan

The study systematically investigated the hypothesis that strategic media initiatives promote and accelerate nation-building processes (NBP) in Sudan. The strategic media variables examined included three essential ones: media language perfection (MLP), qualitative media coverage (QMC), and information building plan (IBP). Using a multilinear regression model (MLRM), the study analyzed the relationships among these predicting variables and their impact on the dependent variable. The evaluation of how the three predictors impact nation-building and state stability required the distribution of a survey containing 21 questions. 200 Sudanese journalists from different parts of the country received the questionnaire. They represent diverse backgrounds across private and public media institutions, including male and female participants. The principal data collection technique adopted by the study was the online survey, supplemented by other secondary sources such as journals, books, and professional internet websites. The use of a five-point Likert scale was feasible to evaluate responses. The analysis indicated that the three predictors collectively explained 94.2% of the variation in NBP (R² = 0.942, p < 0.001). Among these predictors, IBP demonstrated the highest impact (β = 0.624), followed by MLP (β = 0.589) and QMC (β = 0.247). These findings underscore the significant role of professional media in Sudanese nation-building by facilitating practical initiatives and addressing internal conflicts. The study contributes robust empirical evidence and theoretical insights into the efforts of Sudanese journalists, emphasizing the critical role of strategic media in fostering nation-building and enhancing state stability.

Prototype Analysis in Hopfield Networks With Hebbian Learning.

We discuss prototype formation in the Hopfield network. Typically, Hebbian learning with highly correlated states leads to degraded memory performance. We show that this type of learning can lead to prototype formation, where unlearned states emerge as representatives of large correlated subsets of states, alleviating capacity woes. This process has similarities to prototype learning in human cognition. We provide a substantial literature review of prototype learning in associative memories, covering contributions from psychology, statistical physics, and computer science. We analyze prototype formation from a theoretical perspective and derive a stability condition for these states based on the number of examples of the prototype presented for learning, the noise in those examples, and the number of nonexample states presented. The stability condition is used to construct a probability of stability for a prototype state as the factors of stability change. We also note similarities to traditional network analysis, allowing us to find a prototype capacity. We corroborate these expectations of prototype formation with experiments using a simple Hopfield network with standard Hebbian learning. We extend our experiments to a Hopfield network trained on data with multiple prototypes and find the network is capable of stabilizing multiple prototypes concurrently. We measure the basins of attraction of the multiple prototype states, finding attractor strength grows with the number of examples and the agreement of examples. We link the stability and dominance of prototype states to the energy profile of these states, particularly when comparing the profile shape to target states or other spurious states.

Optimizing Bipolar Reset Waveform to Improve Grayscale Stability in Active Matrix Electrowetting Displays.

The electrowetting display (EWD) device is a new type of electrowetting-on-dielectric (EWOD) equipment that can achieve a paper-like display effect under the control of an electric field. In this microfluidic system, the stability of grayscale can be affected by various factors, such as the physicochemical properties of the materials, the device structure, and electric field distribution. To improve the grayscale stability of active matrix electrowetting displays (AM-EWDs), the impact of different polarities of driving voltage on oil backflow was investigated in this study. Based on the driving principles of AM-EWD, an optimized inter-frame bipolar reset driving waveform was designed to overcome oil backflow. The proposed driving waveform maintained the stability of the oil state by periodically and rapidly releasing trapped charges in the dielectric layer through a reverse driving voltage. Additionally, the effect of feed-through voltage on pixel driving voltage was eliminated by compensating for the driving voltage on a common electrode. Finally, the performance of the designed driving waveform was evaluated with a 6-inch AM-EWD driving platform. Compared to the conventional unipolar reset driving waveform, the backflow speed decreased by 2.70 a.u./s. The standard deviation of the display luminance was also reduced by 11.24 a.u. Experimental results indicated that both the oil backflow speed and the fluctuation range of luminance were effectively suppressed by the proposed driving waveform.

Catalytic Fe2+ Cation Pair Site for Base-free N-Alkylation of Aromatic Amines with Alcohols.

The development of heterogeneous Fe catalysts is very attractive due to the ubiquitous, abundant, and inexpensive nature of Fe as a resource. However, Fe oxides are commonly inert as catalysts and hence, the design and fabrication of active Fe sites are essential. Herein, the fabrication of an active Fe cation pair site by simple reduction treatment of SiO2-supported FeOx (FeOx/SiO2) is presented. The active Fe cation pair site was formed by the removal of the oxygen atom between Fe cations of the FeOx on SiO2, namely oxygen vacancy formation, which is induced by temperature-controlled reduction treatment. 773 K reduction maximized the Fe cation pair sites without the decomposition of FeOx species, which was an effective catalytic one for the N-alkylation of amines mainly proceeded through Meerwein-Ponndorf-Verley (MPV) type reduction, which is achieved by the stabilization of six-membered ring transition state derived from imines and alcohols over the open active site of the Fe cation pair site.

Modeling and analyzing stability of hybrid stars within [formula omitted] gravity

This study uses the Krori–Barua type metric to represent hybrid stars within the f(Q) theory of gravity. We postulate that the hybrid star also contains strange quark matter in addition to regular baryonic matter. To investigate the physical viability of the hybrid star model, we present the graphical behavior of the energy density, radial pressure, and tangential pressure, equation of state parameters, anisotropy, and stability analysis, respectively, by choosing the compact star EXO 1785-248 with a mass of 1.3−0.2+0.2M⊙ and radius 8.849−0.4+0.4 km with five different values of the coupling constants as a=2, a=4, a=6, a=8, and a=10. The maximum allowed masses and corresponding radii have been calculated using the M−R curve for three different coupling parameter ’a’ values which match the observational data of three distinct compact stars, namely LMC X-4, SMC X-1, and 4U 1538-52. So, the f(Q) theory of gravity can provide results that are plausible for describing the macroscopical characteristics of hybrid star candidates.

Existence and stability of standing waves for a weakly coupled nonlinear fractional Schrödinger system

We study the system of two weakly coupled nonlinear fractional Schrödinger equations{(−Δ)su+ωu=|u|2p−2u+β|u|p−2u|v|pin RN,(−Δ)sv+ωv=|v|2p−2v+β|u|p|v|p−2vin RN, where N≥2,s∈(0,1],2<2p<2s⁎=2N/(N−2s),ω>0 and β>0. For s∈(0,1] and 1<p<2, by finding a new kind of solution to the above system and comparing its energy level with those of other kinds of solutions, we show that each component of the least energy solution is nontrivial for any β>0, which forms a striking contrast with case p≥2. We emphasize that this result can be viewed as a complement to that of Guo and He (2016) [13] and Maia et al. (2006) [28]. When s∈(0,1),1<p<1+2s/N and ω>0 is fixed, we obtain the orbital stability of standing waves associated with the synchronized solution to the above system. To this end, we introduce an auxiliary mass constraint problem and establish the connection between the orbital stability of standing waves and the stability of ground state set to the auxiliary problem.

Multistate Ferroelectric Diodes with High Electroresistance Based on van der Waals Heterostructures.

Some van der Waals (vdW) materials exhibit ferroelectricity, making them promising for novel nonvolatile memories (NVMs) such as ferroelectric diodes (FeDs). CuInP2S6 (CIPS) is a well-known vdW ferroelectric that has been integrated with graphene for memory devices. Here we demonstrate FeDs with self-rectifying, hysteretic current-voltage characteristics based on vertical heterostructures of 10 nm thick CIPS and graphene. By using vdW indium-cobalt top electrodes and graphene bottom electrodes, we achieve a high electroresistance (on- and off-state resistance ratios) of ∼106, an on-state rectification ratio of 2500 for read/write voltages of 2 V/0.5 V, and a maximum output current density of 100 A/cm2. These metrics compare favorably with state-of-the-art FeDs. Piezoresponse force microscopy measurements show that stabilization of intermediate net polarization states in CIPS leads to stable multibit data retention at room temperature. The combination of two-terminal design, multibit memory, and low-power operation in CIPS-based FeDs is potentially interesting for compute-in-memory and neuromorphic computing applications.

Dynamics of a non-local intraspecific competition predator–prey model with memory effect

In the paper, we investigate a diffusive predator–prey model with nonlocal intraspecific prey competition and spatial memory under Neumann boundary conditions. Through stability and bifurcation analysis, we find that the memory-based diffusion coefficient and the spatiotemporal diffusive delay have important effects on the dynamics of the model. By using the spatiotemporal diffusive delay as a bifurcation parameter, the critical values are determined for the stability of the positive constant steady state and the associated Hopf bifurcation. We find that the system may admit no stability switch, one stability switch and multiple stability switches.

Prenylated Dihydroflavonol from Sophora flavescens Regulate the Polarization and Phagocytosis of Macrophages In Vitro

As an important member of innate immunity, macrophages show remarkable plasticity and heterogeneity, and play an important role in immune regulation, tissue development, homeostasis of the internal environment and injury repair. However, the excessive activation of macrophages is closely related to the occurrence and development of many diseases. The prenylated flavonoid structure is one of the characteristic structures isolated from Sophora flavescens, with anti-inflammatory, anti-tumor, anti-allergy and other effects. In this study, the effects of (2R)-3β,7,4′-trihydroxy-5-methoxy-8-prenylflavanone (TMP), a prenylated dihydroflavonol, on the polarization and phagocytosis of macrophages were systematically studied. In LPS-induced M1-type macrophages, TMP dose-dependently inhibited the expression of COX-2, iNOS and the secretion of NO, IL-1β, IL-6 and IL-18, showing an inhibitory effect on M1 polarization. Further experiments revealed that it was related to the inhibition of TLR4-related AKT/mTOR, MAPK and NF-κB signaling pathways; in IL-4-induced M2-type macrophages, TMP down-regulated the expression of M2-related Arg1, IL-10, TGF-β, CD206 and CD163, as well as the phosphorylation levels of AKT1 and STAT6. For macrophages in a physiological state, it was very important for cells to return from a stress state to a phenotypic stability in the M0 state. These results indicated that TMP negatively regulated the M1/M2 polarization of macrophages, and made them tend to M0 homeostasis, which might provide new theoretical and data support for explaining the anti-inflammatory immunoregulatory activity of Sophora flavescens.

Comparative Analysis of Economic Policy Stability between Monarchical and Republican Systems: A Theoretical Fundamental Research

The difference between monarchies and republics stems from the variation in the sources of authority and the nature of leadership transition. However, the similarity lies in the fundamental tasks accomplished by political systems, as they represent the structures and institutions that manage the relationships between the ruler and the governed within the state. These systems are responsible for organizing public life and achieving stability. The core tasks differ according to the nature of the political systems, whether they are monarchies, republics, or (democratic, authoritarian, or others). Each system has its own features and characteristics that impact the state's stability, either positively or negatively.

Insights into pressure-driven depolarization in PLZST-based antiferroelectric ceramics

Materials showing field-driven antiferroelectric to ferroelectric transformation are interesting for the design of pyroelectric, high strain actuator and high-power dielectric energy storage and discharge devices. The stability of the antiferroelectric and ferroelectric states at room temperature can be chemically tuned by La and Ti co-modification of the antiferroelectric system Pb(Zr1-ySny)O3. Here, we have chosen a composition Pb0.982La0.012(Zr0.60Sn0.30Ti0.10)O3 (PLZST) at the threshold of the antiferroelectric-ferroelectric instability at room temperature and investigated the effect of electric field, temperature and pressure on the stability of the structural-polar states. We show that electric poling transforms irreversibly the antiferroelectric state into a ferroelectric state. Application of hydrostatic pressure ∼100 MPa on the field-stabilized ferroelectric phase, however, restores the antiferroelectric state and depolarizes the system.

Spatiotemporal Dynamics of an Intraguild Predation Model with Intraspecies Competition

Different species in the environment compete with one another for shared resources and suitable habitats. As a result, it becomes crucial to identify the essential components involved in preserving biodiversity. This paper describes the emergence of a wide range of temporal and spatiotemporal dynamics of an intraguild predation (IGP) model with intraspecies competition and Holling type-II response function between the IG-prey and IG-predator. To explore the dynamics of the temporal model, we study the local stability of all the biologically feasible steady states, global stability of the interior steady state, and Hopf bifurcation. Performing partial rank correlation coefficient (PRCC) sensitivity analysis, we picked more sensitive parameters and plotted the stability regions in two-parameter spaces. The dynamics exhibited by the system can demonstrate some important hallmarks noticed in the environments, such as the existence and nonexistence of oscillatory behavior in the IGP model. The analytical formulations for the stability and bifurcation of the coexistence of the steady-state are not easy to obtain, but we have verified numerically that the limit cycle bifurcates from the coexistence of the steady-state and there eventually emerges a chaotic behavior through period-doubling bifurcations. By plotting the largest Lyapunov exponent (LLE), we have verified that the temporal system experiences chaotic behavior. It is demonstrated that in the case of a diffusive system, diffusion may cause the coexistence of the steady state, which is otherwise stable, to become unstable. Criteria for the occurrence of Turing instability connected to the IGP model are derived. Our numerical illustrations demonstrate that diffusion-driven instability develops different stationary patterns based on the different initial conditions and diffusion parameters. The spatiotemporal patterns are observed in the Turing, Hopf–Turing, and Hopf regions.